The development version of FreeBSD 7.0 AMD64 and I386 scale a lot better then linux on SMP systems, which being worked on by the FreeBSD core members to release 7.0-RELEASE , currently it’s frozen and so stable it, I use it in my server which has

A combination of latest freebsd scheduler ULE 2.0 which was developed by Jeff Roberson that is built into FreeBSD 7.0, the libthr threading library and a patch (not commited, yet ? ) that addresses poor scalability of file descriptor locking and some other patches is what made a system with 8 core amd64 cpu and 16 GB of ram outperform linux by a factor of 4 in MySQL tests.

The tests were performed using sysbench OLTP benchmark, a tool designed for testing mysql performance.

Brief test results: Linux is actually a little ( ~ 2% ) faster then FreeBSD for less then 9 clients, but when the number of clients grows to 20 linux performance drops a lot and FreeBSD’s performance stays the same.

More details about the test here:

http://people.freebsd.org/~kris/scaling/mysql.html

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